The present invention relates to an apparatus for preparing pattern data for an industrial machine for processing a workpiece along a desired path. Although the present invention will be described hereinafter with reference to an industrial sewing machine as an example of the industrial machine, the present invention is not limited to such a sewing machine. For example, the present invention can be equally applied to a welding machine or other machines so long as they work along a given path.
Among industrial sewing machines, one by which a desired stitch pattern is formed on a cloth automatically by moving the latter along a flat surface while holding the cloth with pressure, according to sewing data preliminarily programmed and stored in a memory device thereof is known. Such sewing data are usually stored in a recording medium in the memory device such that sewing of any of different patterns can be done easily. As the recording medium, semiconductor memory, magnetic card or floppy disc, etc., may be used, in which informations of sewing machine operation are stored according to the sequence of stitching.
A construction of sewing data includes a control instruction concerning a relative positional shift of the cloth to a needle for each stitch, a moving rate of the cloth for each stitching and a control instruction for controlling the sewing machine and a motor for driving the sewing machine. A control information for each sewing pattern is formed as a collection of these control instructions for each stitch. Therefore, in order to perform a sewing of a desired sewing pattern with this sewing machine, it is necessary to prepare control data corresponding to the desired sewing pattern and store it on the recording medium.
FIGS. 8 and 10 are a perspective view of an example of a conventional sewing data preparating apparatus which is disclosed in, for example, Patent Application Laid Open No. 60-148582, and a hardware construction, respectively. On a front panel of the apparatus is a tablet digitizer 10 which includes a menu portion 11 for inputting data and a pattern input portion 13. A cursor 12 is used for selection on the menu portion 11 and acquisition of coordinate data from the pattern input portion 13. 20 depicts an LED display panel, 26 a CRT for displaying pattern data, which is equipped with a usual key board 50 including ten keys and alphabetic keys, etc. 18 depicts a floppy disc as a memory medium and 16 depicts a floppy disc driver for driving the floppy disc 18 to write sewing data into the floppy disc 18 or read it therefrom.
FIG. 9 shows a detail of the menu portion 11 and an example of the cursor 12 having a read portion 12a and a switch 12b.
An operation of this sewing data preparing apparatus will be described with reference to FIG. 10. By drawing a desired sewing pattern on the tablet digitizer 10 using the cursor 12, sewing data is produced by control operations to be performed mainly by a CPU 14, which is temporarily stored in a RAM 24. Then, the temporarily stored data is written in the floppy disc 18 by the floppy disc driver 16 through a gate 44 and the sewing machine 38 is driven by inserting the floppy disc 18 into the control device 40 as the sewing data recording medium. Settings of various modes during the data formation and operational procedures are displayed on a LED display panel 20 as I/O data through the gate 44. A program for writing the input data from the tablet digitizer 10 through a gate 48 to the floppy disc by the CPU 14 is stored in a system program ROM 22 and the CPU 14 performs required processings according to this program. X and Y coordinate data which are the input data from the tablet digitizer 10 are temporarily stored in the RAM 24 and the variation of the X and Y coordinate data which are stitch data obtained by operating the X and Y coordinate data, that is, the relative value data, are also stored temporarily in the RAM 24. In order to monitor the pattern data inputted from the tablet digitizer 10, a pattern display CRT 26 is provided. The sewing data stored by the CPU 14 in the RAM 24 is transformed into an image display data, stored through a gate 32 in an image data RAM 28 and displayed by a CRT control circuit 46 on the CRT 26 as a stitch pattern to thereby facilitate an input operation by an operator.
FIG. 11 shows an example of stitch pattern, an inputting method of which will be described in detail. First, a drawing bearing the stitch pattern shown in FIG. 11 is attached onto the pattern input portion 13 of the tablet digitizer 10 and then the read portion 12a of the cursor 12 is put on "pattern input" of the menu portion 11 and the switch 12b is depressed to set a pattern input state. Similarly, "scale", "1", "0", "0", "stitch length", "3", ".", "0", "low speed", "point input", "start" are depressed in the order to set the input condition. In this case, the scale is set to 100% so that the size of the drawing is equal to that of the input data, a stitch data of 3.0 mm is set is produced, the sewing speed is set at lower speed and the input method is set as point input.
Thereafter, the read portion 12a of the cursor 12 is put at an original point O in FIG. 11 and the switch 12b is depressed to input the original point. Subsequently, "idle feed", point A.fwdarw.point B.fwdarw."linear input", "high speed", point C.fwdarw."point input", "middle speed 1", point D .fwdarw.point E.fwdarw."linear input", "high speed", point F.fwdarw. "intermediate stop", point G.fwdarw."point input", "middle speed 1", point H.fwdarw.point I.fwdarw."linear input", "high speed", point J.fwdarw."idle feed", Original point O.fwdarw."end" are inputted in the order by the cursor 12 for selection on the menu portion 11 and stitch pattern.
Thus, the input operation of the stitch pattern shown in FIG. 11 is completed. During this procedure, the scale value, the stitch length, the speed instruction value and the input method are displayed on the LED display panel 20 and the stitch pattern is displayed on the CRT 26.
FIG. 12 shows a flowchart of data processing corresponding to the above mentioned input procedures. When the switch 12b of the cursor 12 is depressed in the step S1, the coordinate data are read in the step S2 and it is determined in the step S3 whether the read data is for the selection in the menu portion 11 or the stitch pattern. If it is the former, it is determined in the step S5 which menu is selected and a processing corresponding to the selected menu is performed in the step S6. On the other hand, when it is decided in the step S3 that the stitch pattern is selected, the coordinate data readout in the step S4 is processed and a processing for formation of sewing data with the result of the step S6 and for display them on the LED display panel is performed in the step S7. Thereafter, processings for display of the formed sewing data on the CRT 26 or writing it in the floppy disc are performed.
Since the conventional sewing data preparing apparatus for a sewing machine is constructed as mentioned above, it is possible, by selecting "list display" of the menu portion 11, to recognize the sewing data prepared by inputting sewing speed, feed amount and other control instructions for each stitch before a sewing operation. However, it is impossible to preliminarily know a sewing time necessary for a sewing machine to perform the required sewing because it varies depending upon not only the sewing speed per stitch which can be shown on the "list display" but also the type of the sewing machine and stitch length. In order to know the sewing time of the sewing machine, it must be actually measured by using a stop watch, etc.
Further, when the sewing data written in the floppy disc overflows a sewing range of the machine, the fact can not be known unless a sewing is actually performed.